Process of making piston-rings.



H. S. FRANK.

PROCESS OF MAKING PISTON RINGS.

APPUCATlONFlLED SEPT- 1 19'6- 1,@83,13& Patented Oct. 29, 1918.-

2 $HEETS-$HEET 2- p circumference, are properly proportioned or.

were srn'rns Parana onto,

HARRY S. FRANK, OF ST. LOUIS, MISSOURI, ASSIGNOR TO INLAND MACHINE WORKS,

.0]? ST. LOUIS, MISSOURI. A CORBORATION OF MISSOURI.

IPROCESS OF MAKING PISTON-RINGS.-

Specification of Letters Patent.

Patented Oct. 29, 11918.

against the cylinder will be equally distributed and proportioned throughout their circumference.

An object of the invention is'to provide a novel process for use in the art of manufacturing piston rings, whereby rings of uniform radialthickness may be produced and so characterizedthat, when compressed within the cylinder for which they are intended, they will impart against the cylin der wall a uniform pressure all around, without variation in the pressure as in the case of rings of usual construction.

Another object of the invention is to pro- -vide a process of manufacturing and characterizing piston rings of'the open resilient type and of uniform thickness all around, whereby the stresses .of the rings opposite the cuts, and the pressure of the rings against the cylinder walls throughout their equalized throughout the circumferential portions of the rings. This characterization of the rings and the equalization of the stresses and pressure are attained in rings of the split construction, as well as in rlngs possessing any of the well known cuts, such,

for instance, as the straight, diagonal, or lap-joint cuts.

Another object of the invention is to provide a process of manufacturing piston rings characterized by'any and all of the novel and useful characteristics hereinafter fully described.

Other objects of the invention will appear from the following description, reference being made to the accompanying drawings illustratingrings in different stages of their manufacture, and in which Figure 1 is a side elevation of a ring blank as it appears in a casting or is cut from a cylinder.

Fig. 2 is a side elevation of the ring blank after it has been cut to provide an open resilient blank.

Fig. 3 is a viewshowing the partly formed ring on an arbor, upon which the structure and formation of the ring are changed and the ring is conformed to a new shape.

Fig. 4 is a view showing the ring after it has been given its new. conformation or shape upon the arbor and removed therefrom.

Fig. 5 is a side elevation of the finished rmg.

V Fig. 6 is a sectional view of a cylinder and piston after the finished ring is mounted in connection therewith.

Figs. 7, 8, 9, 10 and 11 are elevations of a piston ring blank of the split type illustrating different stages through which the blank may be passed before being subjected to the final changes in conformation and shape, as a result of which the principal objects of theinvention are attained.

Figs. 12 and 13 are views illustrating the ring upon the arbor, upon which thestructure and formation of the ring are changed and the ring is given its final shape before being finished.

Fig. 14: is a side elevation of the finished ring. I

I Fig. 15 is a sectional view of a cylinder and piston showing the finished spl t ring in connection therewith.

The unfinished ring blank illustrated in Fig. 1 may be in the form of a casting or cut from a blank or cylinder having an external diameter equal to the internal "diameter of the cylinder for which it is intended, plus the quantity of material to be removed in finishing the ring. When the unfinished ring blank illustrated in Fig. 1 is produced, it is in theform of a complete uncut ring, and the next step in the manufacture of the ring, illustrated in Figs. 1 to 6, consists in cutting the-ring as indicated at 1 in Fig. 2,

"in order to provide. a ring of the open reso that the space between the ends of the ring is practically closed when the finished ring is compressed within the cylinder and upon the piston for which it is intended.

The open ring blank is then placed upon an arbor 2 (Fig. 3) which expands the ring to a size in excess of the cylinder for which it is intended by radial pressure imparted at several points. However, While the ends of the rin are spread apart, the radii from the axis 0 the arbor to the ends of the ring remain approximately constant and unvaried, whereas the radii from the axis of the arbor to the portions of the ring in termediate of the ends to the first points of contact. with the arbor are of progressively increasing length, it being understood that the points of contact of the arbor are on the same radii of curvature. Thus, the .portion of the ring which is subjected to expanding pressure by the arbor is on the same radii .of curvature, Whereas the portions of the ring between the ends thereof and the first points of contact with the arbor are on different radii of curvature which are approximately the same as the radii of curvature of the original ring blank.

The ring is next subjected to heat while on the arbor until the structure thereof is changed and corrected by rearrangement of the molecules in conformity with the new shape, so that when the ring is removed from the arbor it retains the size and shape given it thereby. The ring, after it has been subjected to heat and removed from the arbor,

as illustrated in Fig. 4, in which the dotted annular line 3 indicates the original internal diameter of the ring before being placed upon the arbor and subjected to the heat, is turned and finished in any desired manner to produce the complete finished ring shown in Fig. 5. When this finished ring is placed upon a piston and compressed within the cylinder for which it is intended, it forms a proper fit and imparts a uniform radial pressure against the cylinder all around.

The finished ring applied to the piston within the cylinder is illustrated in Fig. 6, the ends of the ring being brought nearly together, and the pressure of the ring against the cylinder bemg approximately uniform throughout the entire circumference of the ring as a result of the conformation of the ring which is efl'ectedjn the manner described.

The ring illustrated in Figs. 7 to 15 inelusive, is a split ring having its ends overlapping for a portion of its circumference and held together throughout their length by the resiliency of the metal, and also having a conformation whereby the radial pressure of the ring is properly proportioned and equalized in order to obtain uniform pressure against the cylinder all around.

. The split ring is produced from an annular means blank and is cut to form a spiral slot 4 from a pointnear one edge of the ring to a diametrically opposite point near the opposite edge thereof as illustrated in Fig. 7. The next operationconsists in cutting narrow slits or cuts through the edges of the ring opposite the ends of the spiral slot as indlcated at- 5, in order to provide a blank for an open resilient ring having overlapping ends. The ring is next inverted, as illustrated in Fig. 9, by reversing the relative positions of the ends by passing one by the other, and the inverted ring thus produced is heated'or hammered to correct and change the arrangement of the molecular structure thereof in conformity with the new shape. Then, the ring is re-inverted to to fit properly within the groove for which it is intende The ring is then placed upon an arbor 6 which expands the rin to a size in excess of the cylinder for whlch it is intended by radial pressure imparted at several points. The extremities of the overlapping portions of the ring are not expanded so that the radii of curvature of the overlapping portions adjacent to the ends thereof remain approximately constant and unvaried, Whereas the radii from the axis of the arbor to the portions between the ends and the first points of contact with the arbor are of progressively increasing length until they attain a length equal to the radii of curvature of the remaining portions of the ring. Thus, the entire portion of the ring which is subjected to expanding pressure by the arbor is given an annular shape, whereas the extremities of the overlapping portions of the ring ,between'the ends thereof and the first points of contact with the arbor are circular arcs having substantially the same radii as the original ring blank. Y

The ring is next subjected to heat while on the arbor, until the molecules thereof are changed in conformity with the new shape,

so that when the ring is removed from the arbor itretains the size and shape given it thereby. The ring, after it has been subjected to heat and removed from the arbor,

as illustrated in Fig. 14, in which the dotted cylinder the ring forms a proper fit and imparts a uniform radial pressure against the cylmder all around.

teams Obviously the order of the operations in giving the ring its final shape is unimportant and may be .varied within the scope of the appended claims.

What I claim and desire to secure by Letters Patent of the United States, is

1. The process of manufacturing piston rings, which consists inexpanding annular, cut rings to a size in excess of the diameter of the cylinder for which they are intended, leaving the end portions of the rings of approximately the same curvature as orig nally, and heating the expanded rings until the tension of the metal is changed and set in the expanded shape.

2. The process of manufacturing piston rings, which consists in expanding annular rings to a size in excess of the diameter of the cylinder for which the are intended, forming the end portions 0 the rings with approximately the same radii of curvature as originally, setting the tension of the rings in their expanded shape, and finishing the rings.

3. The process of manufacturing piston rings, which consists in expanding ring blanks to a size in excess of the cylinders for which they are intended, leaving the end portions of the blanks curving to approximately the same radii of curvature in which 1 they were originally, and setting the tension of the blanks in the shape aforesaid.

4. The process of manufacturing piston rings, which consists in applying pressure to an annular ring to change the shape thereof to an eccentric ring of uniform radial thickness all around, and setting the tension of the metal in the eccentric shape.

5. The process of manufacturing piston rings, which consists in changing the shape of an annular ring to an eccentric shape, setting the tension of the metal in the eccentric shape, and finishing the ring.

6. The process of manufacturing piston rings of uniform radial thickness, which consists in changing the shape of an annular ring to one in' which the greater segmental portion thereof is concentric, and the end portions are eccentric with respect to the greater portion, and setting the tension of the metal in the shape aforesaid.

7. The process of manufacturing piston rings, which consists in applying pressure to a cut ring to give the greater portlon thereof an expanded concentric shape, and leavin the lesser portions thereof adjacent to the cut of the same radii of curvature as originally, and subjecting the ring to heat to set the metal in the shape aforesaid.

8. The process of manufacturing piston rings, which consists in reshaping a cut, unfinished, concentric ring, to a shape in which the ends are of shorter radii of curvature than the remaining segmental portion of the ring, subjecting the ring to heat to set the tension thereof in the new shape, and turning the ring to size.

9. The process of manufacturing piston rings, which consists in mechanically expandlng a circular blank so that one segment thereof is of shorter radius of curvature than the adjacent portion, setting the ring in its expanded shape, and then finishing the ring while in the ex anded shape.

10. The process of manufacturing piston rings, which consists in mechanically expanding a circular metallic blank having a cut therethrough, so that the segments of the ring adjacent to the out are in the form of arcs whose centers are difi'erent from each otherand from the center of the remaining portion of the ring, heating the ring to setthe blank in the expanded shape, and then finishing the ring to size.

11. The process of manufacturing piston rings, which consists in mechanically expanding an open, circular, metallic, unfin ished blank, so that the segments of the blank extending at each-side of the out are of approximately the same radii of curvature as originally and the remainder of the blank of greater radius of curvature, then fixing the blank so that it will remain set in the expanded shape, and then finishing the rlng to size.

12. The process of manufacturing piston. rings, which consists in deflecting an open, annular, metallic blank so that the open ends of the'blank are out of the curvature of the remaining portion thereof and setting the blank in' said shape, then machining the blank to size to produce a finished ring having ilelqual radial pressure throughout its Y fifwitness whereof, I have signed this specification in the presence of two subscribing witnesses.

RnY s. FRANK. 

